package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {


    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;



    @Resource
    private RedissonClient redissonClient;

    private String queueName = "stream.orders";


    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    //异步处理线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    //在类初始化之后执行，因为当这个类初始化好了之后，随时都是有你可能要执行的
    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable{
        @Override
        public void run() {
            while (true){
                try {
                    //1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS stream.orders >
                    //String 消息id  Object, Object kv  'userId' userId  lastConsumed >  count(1)可能有多条List
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create("stream.orders", ReadOffset.lastConsumed())
                    );
                    //2.判断订单信息是否为空
                    if (list == null || list.isEmpty()){
                        //如果为null，说明没有消息，继续下一次循环
                        continue;
                    }
                    //解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    //true 转化有异常抛出
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    //3.创建订单
                    handleVoucherOrder(voucherOrder);
                    //4.确认消息 XACK    record.getId()消息id
                    stringRedisTemplate.opsForStream().acknowledge("stream.orders","g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    //处理异常消息 未xack
                    handlePendingList();
                }
            }
        }
    }

    private void handlePendingList() {
        while (true) {
            try {
                //1.获取pending-list的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS stream.orders 0
                //String 消息id  Object, Object kv  'userId' userId  lastConsumed >  count(1)可能有多条List
                List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                        Consumer.from("g1", "c1"),
                        StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                        StreamOffset.create("stream.orders", ReadOffset.from("0"))
                );
                //2.判断订单信息是否为空
                if (list == null || list.isEmpty()) {
                    //如果为null，说明没有消息，继续下一次循环
                    continue;
                }
                //解析数据
                MapRecord<String, Object, Object> record = list.get(0);
                Map<Object, Object> value = record.getValue();
                //true 转化有异常抛出
                VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                //3.创建订单
                handleVoucherOrder(voucherOrder);
                //4.确认消息 XACK    record.getId()消息id
                stringRedisTemplate.opsForStream().acknowledge("stream.orders", "g1", record.getId());
            }catch (Exception e){
                log.error("处理pending-list中的订单异常",e);
                try {
                    Thread.sleep(20);
                } catch (InterruptedException ex) {
                    throw new RuntimeException(ex);
                }

            }
        }
    }



    //用与线程池处理的任务
    //当初始化完毕后，就会区从队列中那信息
    /*private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024*1024);

    private class VoucherOrderHandler implements Runnable{
        @Override
        public void run() {
            while (true){
                try {
                    //1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                   log.error("处理订单异常",e);
                }
            }
        }
    }*/


    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        //创建锁对象(新增代码)
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁对象
        boolean isLock = lock.tryLock();
        //加锁失败
        if (!isLock){
            //返回错误信息，不重试，重试的话这个是秒杀券，限定一个用户一单
            log.error("不允许重复下单");
            return;
        }
        try {
            //注意：由于是spring的事务是放在threadLocal中,此时的是多线程，事务会失效，这是一个子线程，不是父线程,无法从threadLocal中获取信息
             proxy.createVoucherOrder(voucherOrder);
        } finally {
            //释放锁
            lock.unlock();
        }
    }


    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //1.订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(),String.valueOf(orderId)
        );
        int r = result.intValue();
        //2.判断结果否为0
        if (r != 0){
            //2.1不为0，代表没有购买资格
            return Result.fail(r ==1 ? "库存不足":"不能重复下单");
        }
        //3.获取代理对象(事务)
         proxy = (IVoucherOrderService) AopContext.currentProxy();
        //4.返回订单id
        return Result.ok(orderId);
    }

   /* @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())){
            //尚未开始
            return Result.fail("秒杀尚未开始！");
        }
        //3.判断秒杀是否已经结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())){
            //已经结束
            return Result.fail("秒杀已经结束！");
        }
        //4.判断库存是否充足
        if (voucher.getStock() < 1){
            //库存不足
            return Result.fail("库存不足!");
        }
        Long userId = UserHolder.getUser().getId();
        //创建锁对象(新增代码)
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁对象
        boolean isLock = lock.tryLock();
        //加锁失败
        if (!isLock){
            //返回错误信息，不重试，重试的话这个是秒杀券，限定一个用户一单
            return Result.fail("不允许重复下单");
        }
        try {
            //获取代理对象(事务)
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }

    }*/


    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //5.一人一单逻辑
        //5.1用户id
        Long userId = voucherOrder.getUserId();
        Integer count = query().eq("user_id", userId).eq("voucher_id", voucherOrder).count();
        //5.2判断是否存在
        if (count>0){
            //用户已经购买过了
            log.error("用户已经购买过了");
            return;
        }

        //6.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1") // set stock = stock - 1
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock",0).update(); // where id = ? and stock >0
        if (!success){
            //扣减库存
           log.error("库存不足");
           return;
        }
        save(voucherOrder);

    }
}
